Iss Proxy Advisory Services urged shareholders of NYSE Euronext to back a proposal allowing two investors with 10 percent ownership to call special meetings.

NYSE Euronext, based in New York, agreed in February to be purchased by Frankfurt-based Deutsche Boerse for stock valued at $9.64 billion as of yesterday. NYSE Euronext’s board turned down Nasdaq OMX Group and ICE’s $11.3 billion bid on April 10.